Kelly drive bushing



May 15, 1956 D. RAGLAND KELLY DRIVE BUSHING Filed March 9, 1953 [W i Aw FIG. I.

INVENTOR. Douglas Rag/and,

ATTORNEY.

KELLY DRIVE BUSHING Douglas Ragland, New Orleans, La., assignor, by mesne assignments, to Esso Research and Engineering Company, Elizabeth, N. J., a corporation of Delaware Application March 9, 1953, Serial No. 340,943

3 Claims. (Cl. 25523) This application is directed to a Kelly drive bushing.

it is conventional in the rotary drilling art to use a kelly or Kelly bar attached to the upper end of the String of drill pipe for transmitting rotative movement from the rotary table to the string of drill pipe. The kelly is usually formed with its section in the shape of a regular polygon. For manufacturing convenience a kelly is most often formed with its section as a square but other shapes such as hexagon, triangle, or octagon may be used.

As is well known, it is desirable that the Kelly bushing fit the Kelly bar snugly in order to reduce the amount of slippage which would cause additional wear between the kelly and the bushing. However, the Kelly bar must be free to slide vertically through the bushing and in use the Kelly bar becomes worn. Thus, if the Kelly bushing opening is of a fixed size which fits the Kelly bar snugly when new, after some use the two parts will not fit as snugly as desired and eventually the drive bushing may contact the Kelly bar only on the corners and may eventually fit so poorly as actually to slip and fail to rotate the Kelly bar.

The Kelly drive bushing of the present application is arranged so that it automatically makes allowances for changes in the size of Kelly bar and fits the Kelly bar snugly even though the contacting surfaces of the Kelly bar and of the Kelly bushing become worn.

Other advantages of the present invention will be seen from the following detailed description taken with the drawing in which- Fig. 1 is an elevation partly in section showing an embodiment of the present invention; and

Fig. 2 is a view taken along line 2-2 of Fig. 1.

Turning specifically to the drawing, a body A has generally the form of an annulus. The kelly or Kelly bar B passes through body A. Mounted within body A are driving assemblies C and guide blocks D.

The body A which receives motion from the rotary table, not shown in the drawing, has mounted thereon contacting surfaces which in the embodiment shown are vertically arranged roller bearings 11, said bearings corresponding in number and spacing to the sides of the Kelly bar. in the drawing a square sided Kelly bar is shown and, accordingly, four roller bearing assemblies 11 are mounted on body A.

Drive assemblies C are arranged within body A, said assemblies C being equal in number to the sides of the Kelly bar. Each driving assembly C consists of a body l i having vertical sides 13, 14, 15, and a recess side 16. In the embodiment shown, the side 16 is arranged to receive contacting surfaces for contacting with a side of the Kelly bar bushing; the contacting surfaces used are horizontally extending roller bearings 17 and 18 arranged in recess side 16 which allow free vertical movement of the Kelly bar B. Side is wedge shaped with the taper of the wedge surface decreasing in the direction body A rotates when the hole is being deepened, that is to say, in the direction the bushing rotates the major portion of the time during the actual drilling operations.

" v ted States Patent 0 2,745,636 Patented May 15, 1955 As shown in Fig. 2, the bushing is intended to operate in a clockwise direction as in the drilling operation when making hole and, accordingly, the wedge shaped surfaces 15 of driving assemblies C taper in such direction that the bearings 11 tend to force the horizontally extending roller bearings 17 and 18 into closer contact with the sides of Kelly bar B as the bushing is being driven. This arrangement allows the Kelly bar B to be readily lowered and raised vertically as desired during the actual drilling operation but insures that there is a snug fit between the contacting surfaces of the drive bushing and the Kelly bar B in spite of the wear of parts resulting from use.

Body A is provided with equally spaced recesses 20 at points between the bearings 11, said recesses being arranged for receiving the guide blocks D As will be seen in the drawing, guide blocks D have a cross section similar to that of a cross section of a quarter of a cylinder with sides 21 and 22 joining each other at right angles and adapted to fit snugly against sides 13 and '14, respectively, of members 12. Surfaces 21 and 22 of the guide blocks are joined to arcuate surface 25 by means of rounded corners 26 and 27, said rounded corners 26 and 27 being adapted to contact the rounded corners 28 and 29, respectively, of the recessed openings 29 of body A. Thus, as long as the bushing A rotates in the clockwise direction to the Kelly bar B, the force is transmitted from body A through bearings 11, wedge surfaces 15, bearings 17 and 18 to Kelly bar B. However, when the direction of rotation of the Kelly bar is to be reversed, as is desirable occasionally during the drilling operations, counter-clockwise motion of body A causes the surfaces 29 of the body to contact the curved surfaces 27 of the guide blocks D so that the force is then transmitted through member A to guide blocks D and through surfaces 21 of the guide blocks to corresponding surfaces 16 of assemblies C and then to horizontally extending bearings 17 and 18 to Kelly bar B. Thus, although the device does not provide an automatic tightening means when the kelly is reversed, it does provide means for driving the kelly in a reversed direction and an automatic tightening means for driving the kelly in the normal direction.

A cover E is provided which fits snugly on body A and may be attached thereto by suitable means such as threads 30. Cover E serves to keep the guide blocks D and driving assemblies C in position during use. It will be understood that guide blocks D and assemblies C are both slidably arranged within body A and are designed so that they inherently maintain proper spacing and positioning within the body A.

While a specific embodiment of the present invention has been disclosed, it will be obvious to a workman skilled in the art that various changes may be made in the sizes, shapes and proportions of the several parts shown without departing from the scope of the invention.

I claim:

1. A Kelly drive bushing adapted to drive a Kelly bar having its section in the shape of a regular polygon comprising, in combination, a generally annular body adapted to be arranged with its axis vertical and to be rotated in use at least a major portion of the time in a given direction, said body carrying vertically extending contact surfaces corresponding in number and spacing to the surfaces of the Kelly bar, a plurality of like vertically extending driving assemblies uniformally arranged within the body, with each assembly having a leading edge and a trailing edge with the leading edge of one assembly adjacent the trailing edge of an adjacent assembly, said vertically extending driving assemblies corresponding in number and spacing to the surfaces of the Kelly bar, each vertically extending driving assembly being tapered horizontally and of decreasing thickness from its leading edge to its trailing edge with its outer vertical surface in contact with one of said vertically extending contact surfaces carried by said body, each of said driving assemblies having a side on the opposite side to the outer vertical surface provided with rotatable means providing a horizontally extending contact surface, said driving assemblies being arranged to make contact with the sides of the Kelly bar.

2. A device in accordance with claim 1 in which like blocks equal in number to the sides of the Kelly bar are slidably arranged within said annular body between and in contact with the driving assemblies with each block having surfaces parallel to and in contact with the leading and trailing edges of two adjacent vertically extending driving assemblies, said blocks transmitting power to the driving assemblies When rotating the annular body in an opposite direction.

3. A Kelly drive bushing adapted to drive a Kelly bar having its section in the shape of a regular polygon comprising, in combination, a generally annular body adapted to be arranged with its axis vertical and to be rotated in use at least a major portion of the time in a given direction, the interior surface of said annular body having equally spaced driving recesses corresponding in number to the sides of the Kelly bar, vertically extending roller bearings corresponding in number and spacing to the sides of the Kelly bar mounted on said body between said driving recesses, a plurality of like vertically extending driving assemblies equal in number and spacing to the sides of the Kelly bar uniformally arranged within said body with each assembly having a leading edge and a trailing edge with the leading edge of one assembly adjacent the trailing edge of an adjacent assembly, each vertically extending driving assembly being tapered horizontally and of decreasing thickness from its leading edge to its trailing edge and having its outer vertical surface in contact with one of said vertically extending roller bearings and having its inner vertical opposite side provided with a recess, horizontally extending roller bearings arranged in each of said recesses in the driving assemblies to make contact with one of the sides of the Kelly bar, and blocks equal in number to the sides of the Kelly bar uniformally mounted in the annular body between and in contact with the driving assemblies with a block slidably arranged in each of said driving recesses and having surfaces parallel to and in contact with the leading and trailing edges of two adjacent vertically extending driving assemblies, said blocks transmitting power to the driving assemblies when rotating the annular body in an opposite direction.

References Cited in the file of this patent UNITED STATES PATENTS 

